@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Pretendard:wght@400;500;600;700;800&display=swap');

:root {
  --background: #09090b;
  --surface: #18181b;
  --surface-hover: #27272a;
  --border: #27272a;
  --primary: #2dd4bf;
  --primary-hover: #14b8a6;
  --text-primary: #faffff;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;
  --radius-md: 12px;
  --radius-lg: 24px;
  --transition: 0.2s ease-in-out;
  --font-sans: 'Inter', 'Pretendard', sans-serif;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background-color: var(--background);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  letter-spacing: -0.02em;
}

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

/* Typography */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
}

h1 { font-size: 3.5rem; letter-spacing: -0.04em; }
h2 { font-size: 2.25rem; letter-spacing: -0.03em; margin-bottom: 1rem; }
h3 { font-size: 1.25rem; margin-bottom: 0.5rem; }
p { margin-bottom: 1rem; color: var(--text-secondary); }

/* Header & Nav */
header {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(9, 9, 11, 0.7);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 1000;
  border-bottom: 1px solid var(--border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo::before {
  content: '';
  display: block;
  width: 24px;
  height: 24px;
  background: var(--primary);
  border-radius: 6px;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section {
  padding: 8rem 0;
}

/* Hero Section (Stitch Style) */
.hero {
  padding: 12rem 2rem 8rem;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: 20%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 400px;
  background: radial-gradient(circle, rgba(45, 212, 191, 0.15) 0%, rgba(9, 9, 11, 0) 70%);
  z-index: -1;
  pointer-events: none;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 1rem;
  background: rgba(45, 212, 191, 0.1);
  color: var(--primary);
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 2rem;
  border: 1px solid rgba(45, 212, 191, 0.2);
}

.hero p.lead {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

/* Buttons */
.btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.875rem 2rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition);
  cursor: pointer;
}

.btn-primary {
  background-color: var(--text-primary);
  color: var(--background);
}

.btn-primary:hover {
  background-color: #e4e4e7;
  transform: translateY(-1px);
}

.btn-outline {
  background-color: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  background-color: var(--surface);
  border-color: #3f3f46;
}

/* Content Grid & Cards (Stitch Aesthetic) */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 3rem;
  align-items: center;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
}

.card:hover {
  background: var(--surface-hover);
  border-color: #3f3f46;
}

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--background);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  color: var(--primary);
}

/* Rich Text / SEO Content blocks */
.content-block {
  max-width: 800px;
  margin: 0 auto 5rem;
}

.content-block h2 {
  text-align: center;
  margin-bottom: 2rem;
}

.content-block p {
  font-size: 1.125rem;
  margin-bottom: 1.5rem;
}

.text-highlight {
  color: var(--primary);
  font-weight: 600;
}

/* FAQ Accordion (SEO LSI Keywords) */
.faq-section {
  max-width: 800px;
  margin: 6rem auto 2rem;
}

.faq-title {
  text-align: center;
  margin-bottom: 3rem;
  font-size: 2rem;
}

.faq-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin-bottom: 1rem;
  overflow: hidden;
  transition: var(--transition);
}

.faq-item:hover {
  border-color: #3f3f46;
}

.faq-item summary {
  padding: 1.5rem;
  font-size: 1.125rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  position: relative;
  color: var(--text-primary);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  color: var(--primary);
  font-size: 1.5rem;
  transition: transform 0.3s ease;
}

.faq-item[open] summary::after {
  content: '−';
}

.faq-content {
  padding: 0 1.5rem 1.5rem;
  color: var(--text-secondary);
  line-height: 1.6;
  font-size: 0.95rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 0.5rem;
  padding-top: 1rem;
}

.faq-content strong {
  color: var(--text-primary);
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 4rem 2rem;
  margin-top: 5rem;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
}

.seo-text {
  font-size: 0.875rem;
  color: var(--text-tertiary);
  margin-bottom: 2rem;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.6;
  text-align: justify;
}

.copyright {
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 1.75rem; }
  
  .grid-2 { grid-template-columns: 1fr; gap: 2rem; }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--background);
    flex-direction: column;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border);
  }
  
  .nav-links.show {
    display: flex;
  }
  
  .nav-links li {
    text-align: center;
    padding: 1rem 0;
  }
  
  .mobile-menu-btn {
    display: block;
  }

  .btn-group {
    flex-direction: column;
  }
}